Older adults have higher rates of suicide than younger individuals in the U.S. (and most countries in the world) and the size of the older adult population will rise dramatically in the coming decades, making suicide in later life an issue of pressing public health concern. It is not known how to prevent suicide among older adults; empirical data indicating how to prevent suicide among this high-risk population are notably lacking. The Candidate's career development goal is to be a leading expert in the study of suicide and its prevention in older adults. Reaching that goal requires training in three domains of geriatric research (described below), as well as completion of a mentored research project that will produce substantive, foundational results (also described below). Primary care is a key site for late life suicide prevention: two-thirds or more of older adults who die by suicide are seen by primary-care physicians within a month of their deaths, and up to half within a week. Depressed older adults do not tend to seek specialty mental health treatment. For this reason, Training Objective 1 for this K23 proposal is to gain expertise interfacing with primary care as a site for both recruitment and implementation of innovative interventions with older adults at risk for suicide. It is also known that depression is a strong risk factor for late-life suicide, but te vast majority of depressed older adults do not die by suicide. Further, evidence is beginning to accumulate suggesting that targeting depression in older adults does not sufficiently lower suicide risk among older adults. For example, in the PROSPECT trial, a significant number of older adults remained suicidal at the end of the intervention. Thus, intervention studies targeting older adults at risk for suicide are needed; in particular, we need to understand how these interventions work to effectively implement and disseminate them. For this reason, Training Objective 2 is to gain expertise in the implementation of behavioral intervention protocols for older adults. Depressed older adults frequently present with cognitive impairment. Further, social functioning deficits are also associated with cognitive impairment. Thus, to properly characterize research samples and draw valid inferences from data, the candidate will need to know how to accurately assess cognitive decline. For this reason, Training Objective 3 is to gain knowledge of, and skills assessing, aging-related cognitive decline. The candidate's program of research will be informed by her training and experience as a clinical psychologist, in particular by theoretical and empirical evidence that she helped establish showing the central importance of social disconnectedness to suicide. With the long-term research goal of improving interventions for late-life suicide, the principal objective of the research study proposed here is to examine whether increasing social connectedness -- the degree to which older adults feel connected to, and as if they contribute to, valued relationships -- is a mechanism by which behavioral interventions reduce risk for suicide. To achieve this objective, the candidate requires pilot data demonstrating that a manualized (thus replicable) behavioral intervention does, in fact, increase connectedness while adjusting for correlates of connectedness-depression and cognitive functioning. Despite the likelihood of this association, the question has simply not been comprehensively addressed. This study will recruit n = 100 adults aged 60 years from primary care who endorse both disconnectedness (i.e., feeling lonely and/or like a burden on others) and clinically significant depression. Subjects will be randomly assigned to a behavioral intervention targeting disconnectedness (i.e., Interpersonal Psychotherapy; IPT) or care-as-usual (CAU). At baseline, 3-month, and 6-month assessments, subjects will report on social connectedness, cognitive decline, and depression. The project's Research Aims are: Aim 1: To examine whether a manualized intervention (IPT) can increase connectedness among older adults. Aim 2: To examine whether an intervention targeting social functioning (IPT) also reduces late-life suicide risk. Aim 3: To examine increases in connectedness as a mechanism whereby IPT decreases depression. The resulting findings of this K23 project on depression and death ideation (i.e., indicators of suicide risk) will function as the basis for a larger R01-funded study powered to examine suicide ideation and behavior as outcomes. These findings will be coupled with the candidate's substantial pilot data supporting the link between disconnectedness and both suicide ideation/behavior and depression. Subsequent to this award, the candidate will build on the skills acquired in this period of mentored career development to contribute to the development and refinement of approaches to suicide prevention in later life.